//
// Created by ChaoDONG on 2021-03-24.
//

// names3.c -- use pointers and malloc()
/* names3.c -- 使用指针和 malloc() */
#include <stdio.h>
#include <string.h> /* 提供 strcpy()、strlen() 的原型 */
#include <stdlib.h> /* 提供 malloc()、free() 的原型 */

#define SLEN 81

struct namect {
    char * fname; /* 用指针代替数组 */
    char * lname;
    int letters;
};

void getinfo(struct namect *); /* 分配内存 */
void makeinfo(struct namect *);
void showinfo(const struct namect *);
void cleanup(struct namect *); /* 调用该函数时释放内存 */
char * s_gets(char * st, int n);

int main(void)
{
    struct namect person;
    getinfo(&person);
    makeinfo(&person);
    showinfo(&person);
    cleanup(&person);
    return 0;
}

void getinfo (struct namect * pst)
{
    char temp[SLEN];
    printf("Please enter your first name.\n");
    s_gets(temp, SLEN);
    /* 分配内存储存名 */
    pst->fname = (char *) malloc(strlen(temp) + 1);
    /* 把名拷贝到已分配的内存 */
    strcpy(pst->fname, temp);
    printf("Please enter your last name.\n");
    s_gets(temp, SLEN);
    pst->lname = (char *) malloc(strlen(temp) + 1);
    strcpy(pst->lname, temp);
}

void makeinfo (struct namect * pst)
{
    pst->letters = strlen(pst->fname) +
                   strlen(pst->lname);
}
void showinfo (const struct namect * pst)
{
    printf("%s %s, your name contains %d letters.\n",
           pst->fname, pst->lname, pst->letters);
}
void cleanup(struct namect * pst)
{
    free(pst->fname);
    free(pst->lname);
}
char * s_gets(char * st, int n)
{
    char * ret_val;
    char * find;
    ret_val = fgets(st, n, stdin);
    if (ret_val)
    {
        find = strchr(st, '\n'); // look for newline
        if (find) // if the address is not NULL,
            *find = '\0'; // place a null character there
        else
            while (getchar() != '\n')
                continue; // dispose of rest of line
    }
    return ret_val;
}

